U.S. patent application number 16/214717 was filed with the patent office on 2020-06-11 for side-activated modular drill.
This patent application is currently assigned to KENNAMETAL, INC.. The applicant listed for this patent is KENNAMETAL, INC.. Invention is credited to RUY FROTA DE SOUZA FILHO, HORST MANFRED JAGER.
Application Number | 20200180047 16/214717 |
Document ID | / |
Family ID | 70971522 |
Filed Date | 2020-06-11 |
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United States Patent
Application |
20200180047 |
Kind Code |
A1 |
JAGER; HORST MANFRED ; et
al. |
June 11, 2020 |
SIDE-ACTIVATED MODULAR DRILL
Abstract
A cutting insert includes a head portion having a number of
cutting edges and a centering pin which is disposed about a central
longitudinal axis and which is coupled to, and extends axially away
from, the main head portion. The centering pin includes a recess
structured to accommodate a portion of a setscrew. The recess
includes: a first angled surface disposed generally facing away
from a leading end of the centering pin at an acute first angle
with respect to the longitudinal axis of the centering pin; and a
second angled surface which is positioned opposing the first angled
surface at an acute second angle with respect to the longitudinal
axis of the centering pin.
Inventors: |
JAGER; HORST MANFRED;
(NURNBERG, DE) ; FROTA DE SOUZA FILHO; RUY;
(LATROBE, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KENNAMETAL, INC. |
LATROBE |
PA |
US |
|
|
Assignee: |
KENNAMETAL, INC.
LATROBE
PA
|
Family ID: |
70971522 |
Appl. No.: |
16/214717 |
Filed: |
December 10, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23B 2251/02 20130101;
B23B 2260/0785 20130101; Y10T 408/90993 20150115; B23B 2251/50
20130101; B23B 31/1075 20130101; B23B 51/02 20130101; B23B 2260/124
20130101 |
International
Class: |
B23B 51/02 20060101
B23B051/02 |
Claims
1. A cutting insert comprising: a head portion having a number of
cutting edges; and a centering pin which is disposed about a
central longitudinal axis and which is coupled to, and extends
axially away from, the main head portion, the centering pin
comprising a recess structured to accommodate a portion of a
setscrew, the recess comprising: a first angled surface disposed
generally facing away from a leading end of the centering pin at an
acute first angle with respect to the longitudinal axis of the
centering pin; and a second angled surface which is positioned
opposing the first angled surface at an acute second angle with
respect to the longitudinal axis of the centering pin.
2. The cutting insert of claim 1, wherein the first angle and the
second angle are in the range of 30.degree. to 85.degree..
3. The cutting insert of claim 2, wherein the first angle is about
45.degree..
4. The cutting insert of claim 1, wherein the first angled surface
and the second angled surface are disposed generally parallel.
5. The cutting insert of claim 1, wherein the second angled surface
includes a cutout region disposed about a recess axis which is
structured to accommodate a sub-portion of the setscrew therein
such that at least a portion of the second angled surface
encompasses an angle about the sub-portion of the setscrew, and
wherein the angle is at least 160.degree.
6. The cutting insert of claim 1, wherein the head portion
comprises a number of drive surfaces.
7. The cutting insert of claim 1, wherein the recess is disposed
near a leading end of the centering pin opposite the head
portion.
8. The cutting insert of claim 1, wherein the centering pin
includes a threaded portion disposed at or near a trailing end
thereof which is cooperatively engaged with a corresponding
threaded aperture defined in the head portion such that the
centering pin may be coupled or uncoupled from the head portion via
rotation of one or both of the head portion and/or the centering
pin about a longitudinal axis of the centering pin.
9. The cutting insert of claim 8, wherein the head portion is
formed from a carbide material and the centering pin is formed from
a steel material.
10. The cutting insert of claim 1, wherein the centering pin
includes a circumferential groove extending around the centering
pin near the head portion which is structured to partially fit a
deformable element therein.
11. A centering pin for use in a cutting insert, the centering pin
comprising: an elongated body disposed about a central longitudinal
axis; and a recess structured to accommodate a portion of a
setscrew, the recess comprising: a first angled surface disposed
generally facing away from a leading end of the elongated body at
an acute first angle with respect to the longitudinal axis; and a
second angled surface which is positioned opposing the first angled
surface at an acute second angle with respect to the longitudinal
axis.
12. The centering pin of claim 11, wherein the first angle and the
second angle are in the range of 30.degree. to 85.degree..
13. The centering pin of claim 12, wherein the first angle is about
45.degree..
14. The centering pin of claim 11, wherein the first angled surface
and the second angled surface are disposed generally parallel.
15. The centering pin of claim 11, wherein the second angled
surface includes a cutout region disposed about a recess axis which
is structured to accommodate a sub-portion of the setscrew therein
such that at least a portion of the second angled surface
encompasses an angle about the sub-portion of the setscrew, and
wherein the angle is at least 160.degree..
16. The centering pin of claim 11, wherein the elongated body
includes a threaded portion disposed at or near a trailing end
thereof which is structured to cooperatively engage a corresponding
threaded aperture defined in a head portion of the cutting
insert.
17. The centering pin of claim 11, wherein the elongated body
includes: a circumferential groove extending around the elongated
body which is structured to partially fit a deformable element
therein.
18. A rotary cutting tool comprising: a shank having a pocket; an
interchangeable cutting insert comprising: a head portion
positionable in the pocket, the head portion having a number of
cutting edges; and a centering pin which is disposed about a
central longitudinal axis and which is coupled to, and extends
axially away from, the main head portion, the centering pin
comprising a recess comprising: a first angled surface disposed
generally facing away from a leading end of the centering pin at an
acute first angle with respect to the longitudinal axis of the
centering pin; and a second angled surface which is positioned
opposing the first angled surface at an acute second angle with
respect to the longitudinal axis of the centering pin; and a
setscrew having: a threaded main shaft portion disposed about a
central longitudinal axis, the threaded main shaft portion
threadingly engaged with a correspondingly threaded channel formed
in the shank in a manner such that the can reciprocally translate
within the channel; a narrowed neck region disposed adjacent the
main shaft portion; and a head portion disposed adjacent the
narrowed neck region opposite the main shaft portion, the head
portion defined in-part by a clamping surface disposed at a distal
end of the setscrew opposite the neck region and a bump surface
disposed adjacent the neck region opposite the clamping surface;
wherein the setscrew and the cutting insert are movable among: an
initial position, wherein the cutting tip is initially received in
the pocket and the setscrew is not directly engaged with the
centering pin; a clamped position, wherein the cutting tip is
fixedly held with respect to the shank via engagement between the
clamping surface of the setscrew and the first angled surface of
the recess of the centering pin; and a bump-off position, wherein
the cutting tip is forced outward from the shank via engagement
between the bump surface of the setscrew and the second angled
surface of the recess of the centering pin.
19. The rotary cutting tool of claim 18, wherein the second angled
surface of the recess of the centering pin includes a cutout region
disposed about a recess axis, wherein, when disposed in the
bump-off position the neck region of the setscrew is disposed in
the cutout region, and wherein, when disposed in the bump-off
position, the bump surface of the setscrew and the second angled
surface of the recess of the centering pin are engaged in an
interaction area which encompasses an angle about the longitudinal
axis of the setscrew of at least 160.degree..
Description
BACKGROUND
[0001] A great variety of drills with replaceable cutting tips (or
cutting inserts) are known conventionally. Illustrative examples
may be appreciated via U.S. Pat. Nos. 7,309,196 and 7,467,915 to
Frota de Souza, Filho, and U.S. Pat. No. 9,205,498 to Jaeger. Such
drills involve replaceable cutting heads which are mounted on
shanks. Typically, though by no means exclusively, the cutting
heads and shanks can display continuous and complementing
configuration as fluted drills. Each shank will normally include a
structure for retaining and rotating an associated cutting head,
while the associated cutting head will have a complementing
structure for being retained and rotated by the shank.
[0002] Often, challenges are encountered conventionally with
respect to deformation and failure during the service life of a
drill, due (at least in part) to a concentration of stresses
imposed on the retaining and drive structure of the shank during
ordinary service. This may unduly limit the useful service life of
the drill, thus relevant improvements and modifications continue to
be sought that might help mitigate the effect of known problems and
constraints.
SUMMARY
[0003] In summary, one aspect of the invention provides a rotary
cutting tool comprising: a shank; and an interchangeable cutting
tip; the shank comprising a pocket which receives the
interchangeable cutting tip via an interference fit; the pocket
comprising two centering wall portions which, when viewed along a
central longitudinal axis of the shank, are oriented at a first
angle with respect to one another, the first angle being greater
than zero; the interchangeable cutting tip being axially
displaceable between: an initial position, which is assumed by the
interchangeable cutting tip upon being received in the pocket of
the shank; a clamped position, wherein the interchangeable cutting
tip is fixedly held with respect to the shank; and a bump-off
position, wherein the interchangeable cutting tip is not fixedly
held with respect to the shank; a holding element which holds the
interchangeable cutting tip in the clamped position; and a bump-off
element which displaces the interchangeable cutting tip between the
clamped position and the bump-off position.
[0004] Another aspect of the invention provides a shank for a
rotary cutting tool, the shank comprising: a pocket which receives
an interchangeable cutting tip via an interference fit; the pocket
comprising two centering wall portions which, when viewed along a
central longitudinal axis of the shank, are oriented at a non-zero
angle with respect to one another; a holding element which holds an
interchangeable cutting tip in the clamped position; a bump-off
element which displaces an interchangeable cutting tip between the
clamped position and the bump-off position; and a pair of torque
transmission walls for rotationally driving an interchangeable
cutting insert about the central longitudinal axis of the shank;
the torque transmission walls each being oriented at a
predetermined angle with respect to a defining dimension of at
least one of the centering wall portions, the third angle being
between about 75 degrees and about 120 degrees.
[0005] Yet another aspect of the invention provides a cutting
insert comprising: a head portion having a number of cutting edges;
and a centering pin which is disposed about a central longitudinal
axis and which is coupled to, and extends axially away from, the
main head portion, the centering pin comprising a recess structured
to accommodate a portion of a setscrew, the recess comprising: a
first angled surface disposed generally facing away from a leading
end of the centering pin at an acute first angle with respect to
the longitudinal axis of the centering pin; and a second angled
surface which is positioned opposing the first angled surface at an
acute second angle with respect to the longitudinal axis of the
centering pin.
[0006] A further aspect of the invention provides a centering pin
for use in a cutting insert, the centering pin comprising: an
elongated body disposed about a central longitudinal axis; and a
recess structured to accommodate a portion of a setscrew, the
recess comprising: a first angled surface disposed generally facing
away from a leading end of the elongated body at an acute first
angle with respect to the longitudinal axis; and a second angled
surface which is positioned opposing the first angled surface at an
acute second angle with respect to the longitudinal axis.
[0007] Yet a further aspect of the invention provides a rotary
cutting tool comprising: a shank having a pocket; an
interchangeable cutting insert comprising: a head portion
positionable in the pocket, the head portion having a number of
cutting edges; and a centering pin which is disposed about a
central longitudinal axis and which is coupled to, and extends
axially away from, the main head portion, the centering pin
comprising a recess comprising: a first angled surface disposed
generally facing away from a leading end of the centering pin at an
acute first angle with respect to the longitudinal axis of the
centering pin; and a second angled surface which is positioned
opposing the first angled surface at an acute second angle with
respect to the longitudinal axis of the centering pin; and a
setscrew having: a threaded main shaft portion disposed about a
central longitudinal axis, the threaded main shaft portion
threadingly engaged with a correspondingly threaded channel formed
in the shank in a manner such that the can reciprocally translate
within the channel; a narrowed neck region disposed adjacent the
main shaft portion; and a head portion disposed adjacent the
narrowed neck region opposite the main shaft portion, the head
portion defined in-part by a clamping surface disposed at a distal
end of the setscrew opposite the neck region and a bump surface
disposed adjacent the neck region opposite the clamping surface;
wherein the setscrew and the cutting insert are movable among: an
initial position, wherein the cutting tip is initially received in
the pocket and the setscrew is not directly engaged with the
centering pin; a clamped position, wherein the cutting tip is
fixedly held with respect to the shank via engagement between the
clamping surface of the setscrew and the first angled surface of
the recess of the centering pin; and a bump-off position, wherein
the cutting tip is forced outward from the shank via engagement
between the bump surface of the setscrew and the second angled
surface of the recess of the centering pin.
[0008] For a better understanding of exemplary embodiments of the
invention, together with other and further features and advantages
thereof, reference is made to the following description, taken in
conjunction with the accompanying drawings, and the scope of the
claimed embodiments of the invention will be pointed out in the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 provides an elevational view of a rotary cutting tool
which includes a shank and an interchangeable cutting insert.
[0010] FIG. 2 provides an elevational view of a shank and cutting
insert in a cutting tool 110.
[0011] FIG. 3 provides a plan view of a conventional cutting tool
with a shank, and a cutting insert installed therein.
[0012] FIG. 4 provides a plan view of a shank.
[0013] FIG. 5 provides an elevational view of the shank of FIG.
4.
[0014] FIG. 6 provides a plan view of a shank and cutting insert
installed therein.
[0015] FIG. 7A provides an elevational view of a cutting
insert.
[0016] FIG. 7B provides a plan view of the cutting insert of FIG.
7A.
[0017] FIG. 7C provides an axial section taken through the line
7C-7C in FIG. 7B.
[0018] FIG. 7D provides an elevational view of a cutting insert, in
accordance with at least one variant embodiment.
[0019] FIG. 8 provides essentially the same elevational view as
FIG. 7A, but additionally showing an angled setscrew.
[0020] FIG. 9A schematically illustrates, in an elevational
cross-sectional view, a cutting insert and a setscrew in an initial
position for assembly
[0021] FIG. 9B schematically illustrates the cutting insert and a
setscrew of FIG. 9A, but in a "clamped" position.
[0022] FIG. 9C schematically illustrates the cutting insert and a
setscrew of FIG. 9A, but in a position set for "bump-off" or
disassembly
[0023] FIG. 10 provides a plan view of a shank in accordance with
at least one variant embodiment, including a wrench tool for
displacing a cutting insert.
[0024] FIG. 11A provides a front elevational view of a shank and
cutting insert in a clamped position, in accordance with at least
one variant embodiment.
[0025] FIG. 11B provides an axial section taken through the line
11B-11B in FIG. 11A.
[0026] FIG. 12A provides a side elevational view of a shank and
cutting insert in accordance with at least one variant embodiment
similar to FIG. 11A, but with a wrench tool 1270 inserted, and in a
position set for "bump-off" or disassembly.
[0027] FIG. 12B provides a rear elevational view of the shank and
cutting insert shown in FIG. 12A.
[0028] FIG. 12C provides an axial section taken through the line
12C-12C in FIG. 12B.
[0029] FIG. 12D provides an axial section taken through the line
12D-12D in FIG. 12A.
[0030] FIG. 13A provides an elevational isometric view of a cutting
insert.
[0031] FIG. 13B provides an axial section taken through the line
13B-13B in FIG. 13A.
[0032] FIG. 13C provides a detail view of the portion of FIG. 13A
indicated at 13C in FIG. 13A.
[0033] FIG. 13D provides a sectional view such as taken through the
line 13D-13D in FIG. 13B.
[0034] FIG. 14 provides an isometric view of a setscrew.
[0035] FIG. 15A schematically illustrates, in an elevational
cross-sectional view, a cutting insert and a setscrew in an initial
position for assembly in a shank.
[0036] FIG. 15B schematically illustrates the cutting insert and
setscrew of FIG. 15A, in an positioning in which the setscrew
initially engages the cutting insert.
[0037] FIG. 15C schematically illustrates the cutting insert and
setscrew of FIG. 15A in another positioning in which the engagement
between the setscrew and the cutting insert has forced the cutting
insert further into the shank.
[0038] FIG. 15D schematically illustrates the cutting insert and
setscrew of FIG. 15A, but in a "clamped" position in the shank.
[0039] FIG. 15E schematically illustrates the cutting insert and
setscrew of FIG. 15A, but in a position set for "bump-off" or
disassembly of the cutting insert from the shank.
[0040] FIG. 15F provides a detail view of the portion of FIG. 15D
indicated at 15F in FIG. 15D.
[0041] FIG. 15G provides a detail view of the portion of FIG. 15E
indicated at 15G in FIG. 15E.
[0042] FIG. 15H provides a sectional view, similar to FIG. 13D,
which shows, the interaction area between the cutting insert and
setscrew of FIG. 15E such as taken through the line 15H-15H in FIG.
15E.
DETAILED DESCRIPTION
[0043] It will be readily understood that the components of the
embodiments of the invention, as generally described and
illustrated in the figures herein, may be arranged and designed in
a wide variety of different configurations in addition to the
described exemplary embodiments. Thus, the following more detailed
description of the embodiments of the invention, as represented in
the figures, is not intended to limit the scope of the embodiments
of the invention, as claimed, but is merely representative of
exemplary embodiments of the invention.
[0044] Reference throughout this specification to "one embodiment"
or "an embodiment" (or the like) means that a particular feature,
structure, or characteristic described in connection with the
embodiment is included in at least one embodiment of the invention.
Thus, appearances of the phrases "in one embodiment" or "in an
embodiment" or the like in various places throughout this
specification are not necessarily all referring to the same
embodiment.
[0045] Furthermore, the described features, structures, or
characteristics may be combined in any suitable manner in at least
one embodiment. In the following description, numerous specific
details are provided to give a thorough understanding of
embodiments of the invention. One skilled in the relevant art may
well recognize, however, that embodiments of the invention can be
practiced without at least one of the specific details thereof, or
can be practiced with other methods, components, materials, et
cetera. In other instances, well-known structures, materials, or
operations are not shown or described in detail to avoid obscuring
aspects of the invention.
[0046] As used herein, the term "about", when used in conjunction
with numerical values, is intended to cover such numerical value as
well as values within reasonable tolerances of such value as would
be recognized by one of ordinary skill in the art.
[0047] The description now turns to the figures. The illustrated
embodiments of the invention will be best understood by reference
to the figures. The following description is intended only by way
of example and simply illustrates certain selected exemplary
embodiments of the invention as claimed herein. To facilitate
easier reference, in advancing from FIG. 1 to and through FIG. 15H,
a reference numeral is advanced by a multiple of 100 in indicating
a substantially similar or analogous component or element with
respect to at least one component or element found in one or more
earlier figures among FIGS. 1-15H.
[0048] FIG. 1 shows a rotary cutting tool 10 in the form of a
drill, having a shank 12 and a cutting insert 14, which are both
produced as separate parts. The cutting insert 14 can be fastened
to, or installed on, the shank 12 in a detachable and
interchangeable manner. Similarly, the rotary cutting tool, for
performing rotary cutting operations on a workpiece, can also be
designed as a countersinking, milling or reaming tool. For purely
illustrative purposes, the cutting tool 10 shown in FIG. 1 is a
twist drill which includes a pair of helical flutes 16 disposed
along the sides of the drill, in diametric opposition to one
another. Each flute 16 extends over the shank 12 and the cutting
insert 14, wherein the latter also includes a drill point 17.
[0049] Generally, a central longitudinal axis A is defined through
the cutting tool 10 (common to both the shank 12 and the cutting
insert 14), about which the cutting tool 10 rotates during
operation. A "cutting insert" may alternatively be referred to,
herein and elsewhere, with any of a variety of other suitable terms
such as "tip", "insert", "head", "cutting tip" or "cutting
head".
[0050] It should be noted that each flute 16, as shown in FIG. 1,
includes portions that are disposed in both the shank 12 and the
cutting insert 16 alike. Thus, once cutting insert 14 is installed
on shank 12, corresponding flute portions in the cutting insert 14
and shank 12, alike, will align to form flutes 16 that are
generally continuous and undistorted. Although two flutes 16 are
depicted herein, it should be understood that any number of flutes
(including only one) is possible.
[0051] FIG. 2 provides an elevational view of a shank 112 and
cutting insert 114 in a cutting tool 110, in accordance with at
least one embodiment. As shown, the cutting insert 114 is fixedly
positioned at an axial end of the shank 112, in preparation for
operation. Further details of a shank and cutting insert in
accordance with at least one embodiment will be better appreciated
from the ensuing discussion.
[0052] In the depiction of FIG. 2, cutting head 114 emerges at a
leading end of cutting tool 110. A "leading end", defined herein
for semantic purposes, represents that end which engages a work
piece when cutting. During cutting operations, cutting tool 110 is
rotated, and advanced progressively into a workpiece as cutting
progresses. That end of cutting tool located oppositely to the
leading end can be referred to as the "trailing end". The terms
"leading end" and "trailing end" are semantic devices which apply
equally to shank 12 and cutting head 14 as they connote directional
orientation with respect to longitudinal axis A rather than
specific structure.
[0053] By way of general comparison in accordance with at least one
embodiment, FIG. 3 provides a plan view of a conventional cutting
tool 210 with a shank, and a cutting insert installed therein. As
shown, the insert 214 is mounted at an axial end of the shank 212,
for engaging in a cutting operation when the cutting tool 210 is
rotated about longitudinal axis A in a counter-clockwise cutting
direction C (when viewed with respect to FIG. 3). The tool 210
includes a pair of flutes 216 defined via mutual positioning of the
shank 212 and insert 214 with respect to one another. The insert
214 is received in a pocket of the shank 212 via an interference
fit.
[0054] Cutting insert 214 includes a pair of cutting edges 220,
each disposed adjacent to a respective flute 216. As can be
appreciated, the cutting edges 220 will cut into a workpiece as the
drill 210 is rotated in cutting direction C when engaging a
workpiece. For the purpose of rotatably driving the cutting insert
214, the same includes two drive surfaces 222 that are dimensioned
and disposed in a manner to be engaged by compatible torque
transmission walls 224 of the shank 212. The drive surfaces 222 and
torque transmission walls 224, alike, are usually each oriented
along a plane that is essentially parallel with respect to
longitudinal axis A. Though not explicitly illustrated here,
rotation of the entire cutting tool 210 can be actuated via a
separate driving element, such as a hand drill, drill press or
machine tool, which causes the shank 212 to rotate.
[0055] As such, with the conventional arrangement illustrated in
FIG. 3, the walls 224 and drive surfaces 222 alike are oriented in
a direction (as shown in the figure) that results in a torque
transmission force that is largely directed perpendicularly to the
walls of the aforementioned pocket (that receives the insert 214
via interference fit). It has been found that this torque
transmission force can produce significant stresses in critical
regions of the shank 212 due to bending, thus representing a
significant place for improvement. For centering and stability. To
the extent that the insert 214 is mounted with an interference fit
for a purpose of centering and stability, it can be appreciated
that elastic deformation of the walls 224 creates stresses in the
same areas as stresses caused by torque transmission. As will be
appreciated more fully herebelow, broadly contemplated herein are
arrangements for a drill where, advantageously, an interference fit
is provided between an insert and a shank wherein high torque
transmission capability is achieved by positioning the drive walls
at a smaller angle (than is the case in FIG. 3) with respect to
pocket centering walls.
[0056] FIG. 4 provides a plan view of a shank 412 in accordance
with at least one embodiment. A pair of flute portions 416b are
defined in the shank and are configured to interface with
compatible flute portions of a cutting insert. Shank 412 includes a
pocket 428 for accommodating a cutting insert; the principal
elements of the latter include two centering walls 432
interconnected by a floor 430. The floor 430 can be oriented
transversely with respect to central longitudinal axis A. Any or
all of central floor portion 430 and centering walls 432 serve as
abutment surfaces which contact a cutting insert when the cutting
insert is installed on shank 412. As shown, a central (blind) hole
or opening 426 is disposed centrally in the floor 430 (about axis
A), and is configured to receive a centering pin of a cutting
insert.
[0057] In a manner to be appreciated more fully below, the
centering walls 432 deform to receive compatible portions of a
cutting insert via an interference fit. Preferably, the centering
walls 432 (or at least a portion thereof) are each inclined at an
angle with respect to the central longitudinal axis A, inclined
away from axis A in progressing toward a leading end of the shank
412. In accordance with at least one embodiment, as shown in FIG.
4, centering walls 432 are substantially straight (while inclined
as noted), and parallel to one another, when viewed in a given,
single horizontal plane that is transverse to axis A. (Here, it can
also be understood that the centering walls 432 would, by
extension, also be inclined with respect to that plane transverse
to the axis A.)
[0058] In accordance with at least one variant embodiment,
centering walls 432 may each be curved when viewed in a given,
single horizontal plane that is transverse to axis A. In such
variants, merely by way of illustrative and non-restrictive
example, each wall 432 may be oriented along an arc that is
substantially parallel to a circumference of the greater shank 412.
Accordingly, taken together, such walls 432 would trace a generally
frustoconical shape, narrowing as a function of proximity (in an
axial direction) to the pocket floor 430.
[0059] Also shown in FIG. 4 are torque transmission walls 424
which, unlike the conventional example of FIG. 3, are configured
and disposed to transmit a force to compatible drive surfaces of a
cutting insert in a in a direction substantially parallel to the
centering walls 432 This represents a significant improvement over
the conventional example of FIG. 3, in that stresses produced in
each of several critical areas of the pocket 428, of other portions
of the shank 412, and of a cutting insert mounted therein, are
considerably reduced.
[0060] Further advantages may be found in connection with insertion
of a cutting insert into pocket 428. Here, to the extent that
centering walls 432 end up deflecting radially outwardly with
respect to axis A, such deflection may be transmitted to the torque
transmission walls 424. However, in so doing, the torque
transmission walls will deflect virtually in parallel to a radial
direction with respect to axis A or very close thereto, essentially
along their own horizontal dimension (that is, their dimension that
is transverse to the axis A). This helps maintain face-to-face
contact with drive surfaces of the cutting insert being clamped. In
contrast, with a conventional arrangement such as that shown in
FIG. 3, the torque transmission walls 224 therein shown will more
or less deflect in a radial direction with respect to axis A, thus
jeopardizing full face-to-face contact with cutting insert drive
surfaces (such as those indicated at 222 in FIG. 3).
[0061] In the arrangement shown in FIG. 4, torque transmission
walls 424 are oriented in parallel with respect to the central
longitudinal axis A, when viewed in a generally longitudinal
direction. In at least one variant embodiment, the walls 424 may be
inclined with respect to the central longitudinal axis A (e.g. at
an angle of between about 0 and about 10 degrees, preferably
between about 2 and about 6 degrees, and/or may match the
inclination of centering walls 432), in a direction opposite to the
rotational cutting direction C of the shank 412, toward the leading
end of the shank 412). (Here, it can be understood that in such a
variant the torque transmission walls 424 would, by extension, also
be inclined with respect a plane transverse to the central
longitudinal axis.) Shallow semi-cylindrical troughs 434 may run
along a bottom of each of the centering walls 432 and torque
transmission walls 424, respectively; the troughs 434 can assist in
reducing the stresses applied to the pocket 428 and to an insert
alike.
[0062] In accordance with the aforementioned variant embodiment,
when walls 424 are inclined with respect to axis A, it should be
noted that when an insert is first positioned in the pocket 428,
before clamping, the centering walls 432 and corresponding surfaces
on the insert will make contact; there will be a gap between the
insert and pocket floor 430 at that point. At the same time, there
will be exist at that point another gap (though a significantly
smaller one) between drive surfaces of the insert (e.g., such as
drive surfaces 722 of the insert 714 shown in FIGS. 7A and 7B) and
torque transmission walls 424. In this manner, when the insert is
clamped and the centering walls 432 expand outwardly, the torque
transmission walls 424 and corresponding drive surfaces on the
insert may come into contact before any torque is applied to the
insert (e.g., as may be applied in a subsequent drilling
operation).
[0063] Generally, it can be appreciated with regard to various
embodiments herein that an insert, when fully clamped in a shank
(such as 412), the insert may contact the pocket floor 430, or
there may indeed be a small gap between a bottom portion of a main
head portion of the insert and the floor 430. Accordingly, while
various views herein may not explicitly illustrate such a gap
(e.g., for general ease of illustration), it should be understood
and appreciated that such a gap can be considered to be present in
accordance with one or more embodiments and/or variants.
[0064] FIG. 5 provides an elevational view of the shank 412 of FIG.
4. As shown, the centering walls 432 can be inclined symmetrically
with respect to axis A and at a mutual angle B with respect to one
another. The angle B could represent an angle of between about 3
and about 6 degrees, or alternatively could be defined as imparting
to each wall 432 a slope of between about 1:20 and about 1:10. It
should be understood and appreciated that, when being installed, a
cutting insert initially will sit on centering walls 432 at a
distance from the pocket floor 430 before it is fully clamped
within the pocket 428. Accordingly, elastic deformation of the
centering walls 432 will occur as the insert is pulled against the
floor 430. (Further details relating to a clamping action, in
accordance with at least one embodiment, will be better appreciated
from the discussion further below.)
[0065] It can be further appreciated, in accordance with at least
one embodiment, that with angled centering walls 432 as discussed
above, interference caused upon initial insertion of a cutting
insert will give rise to a relatively small displacement that then
will be needed in fully clamping the insert within pocket 428 and
in bumping-off the insert in order to then remove the insert. This
stands in stark contrast to conventional arrangements with straight
centering walls (relative to axis A) which typically give rise to a
relatively larger displacement needed for fully clamping an insert
within a pocket, and in then bumping-off the insert.
[0066] In accordance with at least one embodiment, as shown in FIG.
5, substantially the entirety of each centering wall 432, extending
axially upwardly from the pocket floor 430 to the leading end of
shank 412, is inclined as shown. In accordance with at least one
variant embodiment, a lower portion of each centering wall 432
(i.e., a portion axially closer to pocket floor 430) is either not
inclined at all (i.e., is parallel) with respect to axis A or is
inclined at a different angle with respect to axis A than is an
upper portion of each centering wall 432. In such variants, the
upper portions of centering walls 432 can be understood to assume
the angle B discussed above, and would still represent surfaces
initially contacted by an insert, as the insert is received in
pocket 428. In such variants, preferably at least about 50 to 75
percent of the axial extent of each centering wall 432 is
represented by an upper portion which is inclined to assume the
angle B discussed above.
[0067] FIG. 6 provides a plan view of a shank 612 and cutting
insert 614 installed therein, in accordance with at least one
embodiment. As shown, the cutting insert 614 includes drive
surfaces 622 that are oriented to be compatible with torque
transmission walls 624 of the shank 612. Preferably, when viewed
transversely with respect to axis A (as indeed shown in FIG. 6),
surfaces/walls 622 and 624 alike can be oriented such that a
driving force is transmitted generally in a direction substantially
parallel to the centering walls. As such, surfaces/walls 622 and
624 alike can be oriented at an angle D with respect to centering
walls of the shank 612 (such as those indicated at 432 in FIGS. 4
and 5), and thus to a corresponding surface or side 623 of insert
614. By way of illustrative example, D could be between about 75
and about 120 degrees, or preferably between about 85 and about 100
degrees; most preferably, D can be approximately 90 degrees. It
should be appreciated, in this vein, that a workable balance can
preferably be found in choosing angle D, in that larger angles will
tend reduce to stresses on insert 614 and increase stresses on the
pocket (defined via centering walls of the shank 612), while
smaller angles will tend to reduce stresses on the pocket (of shank
612) and increase stresses on the insert 614. It should be further
appreciated that an arrangement such as that shown in FIG. 6 stands
in stark contrast to that shown in FIG. 3, where an angle analogous
to D would be well over 120 degrees, not even far from 180
degrees.
[0068] Generally stated, in accordance with at least one
embodiment, the torque transmission walls 624 (and preferably the
drive surfaces 622, when insert 614 is mounted in shank 612) can
each be oriented at a predetermined angle (e.g., angle D) with
respect to a defining dimension of at least one centering wall
portion of shank 612 (which may be analogous to one or more
centering walls such as those indicated at 432 in FIGS. 4 and 5).
If the at least one centering wall portion is substantially
straight when viewed in a given, single horizontal plane that is
transverse to axis A, the defining dimension can be understood as a
dimension in parallel with respect to the at least one centering
wall portion. If, in accordance with at least one variant
embodiment as described further above, the at least one centering
wall portion is curved when viewed in a given, single horizontal
plane that is transverse to the axis A (and, e.g., along an arc
that is substantially parallel to a circumference of the greater
shank 612), then the defining dimension can be understood as a
tangent of the curvature of the at least one centering wall portion
at a midpoint of the at least one centering wall portion.
[0069] FIG. 7A provides an elevational view of a cutting insert
714, in accordance with at least one embodiment. As shown, a
generally cylindrical centering pin 735 extends axially away from a
main head portion (or head) 736. A recess (or notch) 738 is
provided in the shaft portion 735 to accommodate a setscrew, in a
manner to be more fully appreciated herebelow. Such a recess can be
configured in any suitable manner; by way of illustrative and
non-restrictive example (and indeed as shown in FIG. 7A), it could
be defined by a relatively flat surface oriented in parallel to a
chord or secant defined by the cylindrical pin 735, flanked on the
two axial sides by angled surfaces, one per side, that converge on
the flat surface from an external circumference defined the pin
735. Also shown in FIG. 7A are cutting edges 720, drive surfaces
722 and a cutting tip 717 which may be regarded as analogous to
similar components described and illustrated elsewhere herein. In a
variant embodiment, two symmetrical notches/recesses 738 may be
provided, disposed diametrically opposite from one another with
respect to shaft portion 735.
[0070] FIG. 7B provides a plan view of the cutting insert 714 of
FIG. 7A. As shown, the drive surfaces 722 may be oriented in
similar fashion to those indicated at 622 in FIG. 6.
[0071] FIG. 7C provides an axial section taken through the line
7C-7C in FIG. 7B. Here, in particular, some viable proportional
dimensions of recess 738 are shown.
[0072] FIG. 7D provides an elevational view of a cutting insert
714, in accordance with at least one variant embodiment. Here, in
place of the recess/notch 738 from FIGS. 7A-7C, there is an annular
groove 739 for accommodating a setscrew. As shown, annular groove
739 may be recessed into centering pin 735 about an entire
circumference of pin 735. Groove 739 may further be defined,
substantially as shown, by an inner cylindrical surface (of lesser
diameter than the remainder of centering pin 735 itself), flanked
on the two axial sides by frustoconical surfaces, one per side,
that converge on the inner cylindrical surface from an external
circumference defined by the pin 735.
[0073] FIG. 8 provides essentially the same elevational view as
FIG. 7A, but additionally showing an angled setscrew 840 in
accordance with at least one embodiment. As shown, setscrew 840 may
be inclined at an angle E with respect to the horizontal (i.e., to
a plane which is transverse to axis A), to engage the recess 834 in
a manner to be more fully appreciated herebelow. Setscrew 840, for
its part, may be threadedly engaged in a compatible channel in
order to translate in parallel to its own central longitudinal
axis. To this end, it may be actuated at a rear portion thereof
(i.e., at that end portion disposed away from recess 838), via a
wrench tool or other arrangement that can displace the setscrew 840
in a rotational direction (about its own central longitudinal axis)
to thereby translate the setscrew 840 via the aforementioned
threaded engagement.
[0074] In accordance with at least one embodiment, FIG. 9A
schematically illustrates, in an elevational cross-sectional view,
a cutting insert 914 and a setscrew 940 in an initial position for
assembly. While in this illustration the centering pin 935 (of
insert 914) includes an annular groove 939 (e.g., similar to that
indicated at 739 in the view of FIG. 7D), it should be understood
that the ensuing discussion can also apply to the case of engaging
with a recess or notch, e.g., similar to the one indicated at 738
in FIG. 7A.
[0075] As shown in FIG. 9A, setscrew 940 may be disposed in a
dedicated channel (or hole) 942 in a manner to reciprocally
translate within the channel/hole 942. As noted above, such
movement may be promoted via mutual threaded engagement between
setscrew 940 and channel/hole 942, but in accordance with at least
one variant embodiment the setscrew 940 may be slidingly disposed
within the channel/hole 942. In accordance with at least one other
variant embodiment, the setscrew 940 and channel/hole 942 may be
configured such that part of the reciprocal movement is via
threaded engagement and part of such movement is via sliding
displacement.
[0076] For its part, in accordance with at least one embodiment,
the setscrew 940 includes a main shaft portion 944 and a head
portion 946, with a narrowed neck region 947 disposed therebetween.
Head portion, as shown, may be tapered (e.g., via a frustoconical
outer surface) in a direction generally toward the insert 914. A
distal end of setscrew 940 (i.e., an end disposed toward the insert
914 with respect to an axial direction of the setscrew 940) may
also be defined by a flat, circular end surface 948.
[0077] In accordance with at least one embodiment, groove 939 may
include a first angled surface 950 (disposed toward a trailing end
of centering pin 935), a second angled surface 952 (disposed toward
a leading end of centering pin 935) and an inner cylindrical wall
954 extending therebetween. As such, first angled surface 950 may
be dimensioned so as to engage with the end surface 948 of setscrew
940 as shown (in the initial position for assembly). It should be
understood and appreciated that similarly configured and disposed
surfaces may be provided the case of a recess that does not extend
fully about a circumference of centering pin 935 (e.g., such as
recess 738 in FIG. 7A). Further, while angled surfaces 950/952 and
cylindrical wall 954 are shown and described by way of
non-restrictive and illustrative example, it should be understood
that variants on these may be employed. For instance, wall 954 need
not necessarily be cylindrical, e.g., it may be inclined with
respect to axis A and even could assume two or more distinct
portions along an axial dimension. Angled surfaces 950/952 may,
themselves, be angled differently than shown in FIG. 9A and could
even run strictly transversely with respect to axis A.
[0078] In accordance with at least one variant embodiment, setscrew
940 may be configured without a narrowed neck region 947 such that
it merely terminates, at its distal end, via a beveled outer
surface that converges to a flat, circular end surface. In such a
variant, "bump-off" can be undertaken by way of a wrench tool such
as that indicated at 1070 in FIG. 10 (and as described in further
detail herebelow). For clamping, the setscrew can be positioned at
an angle E (as referenced in FIG. 8) such that either the end face
thereof sits on surface 950, or the beveled/frustoconical outer
surface of the setscrew sits on surface 950; either way, this can
create an axial clamping force that still urges the cutting insert
914 in direction H1 as shown in FIG. 9B.
[0079] As shown, the shank includes a central hole 926 for
accommodating the centering pin 935 of cutting insert 914.
Preferably, the centering pin 935 will have a precise slide fit
with respect to the central hole 926. As such, the side component
of the clamping force created by the setscrew 940 will be supported
by the wall of hole 926, thus preventing excessive displacement of
the pin; it can be appreciated that any such excessive displacement
could otherwise cause the insert 914 to lose its concentricity with
the axis of rotation A, and/or cause breakage of the pin 935. The
combination of a precise fit between pin 935 and hole 926, in
conjunction with the interference fit between insert 914 and a
pocket of shank 912 (such as pocket 428 in FIG. 4) will ensure that
the insert 914 is clamped in a correct position and remains stable
in its position during operation. As such, it can be appreciated
that in at accordance with at least one embodiment the hole 926 and
pin 935 may assume a circular cross-section when viewed
two-dimensionally (in a plane transverse to axis A), and a
generally cylindrical configuration when viewed
three-dimensionally. However, in accordance with at least one
variant embodiment, the hole 926 and pin 935 may assume any of a
wide variety of other possible two-dimensional cross-sectional
shapes, e.g., an oblong (stadium) or elliptical shape.
[0080] The central hole 926 may also include a lowermost portion
(toward the trailing end of shank 912), or floor 955. To help
ensure that the pin 935 (and of cutting insert 914) initially sits
at a predetermined position for proper engagement with the front
portion 946 of setscrew 940, a deformable element 956 may be
provided between that lowermost surface 957 and the floor 955.
Preferably, the deformable element 956 biases the centering pin 935
upwardly (i.e., toward a leading end of shank 912). Merely by way
of illustrative and non-restrictive example, the deformable element
956 may take the form of an O-ring, a spring or a ball plunger. In
accordance with a variant embodiment, a similar or analogous
deformable element may be placed--as an alternative to element 956
or in addition thereto--on the floor of a pocket, such as floor 430
shown in FIGS. 4 and 5; this alternative or additional element
would then bias axially upwardly a seating surface of an associated
cutting insert.
[0081] As shown, in FIG. 9A, the end surface 948 of setscrew 940
contacts the first angled surface 950 of shaft 935 over an initial
contact area, itself shown within the dotted circle 958. The manner
of engagement between setscrew 940 and shaft 935 then changes in a
manner to be appreciated more fully herebelow.
[0082] In accordance with at least one embodiment, FIG. 9B
schematically illustrates the cutting insert and a setscrew of FIG.
9A, but in a "clamped" position. To achieve a "clamped" position,
the setscrew 940 is translated within channel 942 (e.g., via
rotation and the aforementioned threaded engagement), in a
direction Gl, to cause the shaft 935 (and thus the cutting insert
914) to move axially downwardly (i.e., in direction H1). This will
cause the entire cutting insert 914 to move axially downwardly in a
pocket of the shank 912 (e.g., such as pocket 428 in FIGS. 4 and
5), whereupon centering walls of the pocket (e.g., such as walls
432 in FIGS. 4 and 5) will deform elastically in a radially outward
direction (with respect to axis A). This will then promote an
interference fit of the insert 914 within shank 912 (as also
discussed hereabove), such that the insert 914 is then securely
clamped within shank 912. Also, once in the "clamped" position, the
deformable element 956 is deformed in an axial direction of the
insert 914 and the end surface 948 of setscrew 940 comes to contact
the first angled surface 950 over a somewhat larger area (e.g., as
denoted within dotted circle 960) than was the case in the initial
assembly position (see FIG. 9A, and dotted circle 958).
[0083] In accordance with at least one embodiment, FIG. 9C
schematically illustrates the cutting insert and a setscrew of FIG.
9A, but insert still in a "clamped" position and setscrew already
positioned for bump-off. As such, the "bump-off" action takes place
when the setscrew 940 undergoes reverse translational movement, as
indicated by arrow G2, then (via an upper bump-off surface 964 of
head portion 946) contacts the second angled surface 952 in a
manner as shown within dotted circle 962. This then causes the
centering pin 935 (and cutting insert 914) to displace axially in a
"return" direction as indicated by arrow H2. The insert will be
pushed out of pocket and must overcome the frictional forces
exerted by the pocket walls (due to interference fit).
[0084] In accordance with at least one embodiment, the surfaces 952
and 964 described and illustrated with respect to FIGS. 9A-9C may
preferably be oriented in a horizontal direction, that is,
perpendicular to axis A. This will help facilitate a bump-off force
that is applied substantially in an axial direction (H2).
[0085] Preferably, surfaces 948 and 950 may be oriented
substantially in parallel with respect to one another, in order to
facilitate direct engagement in applying and distributing a
clamping force, as well as mutual sliding engagement when
transitioning between an initial position for assembly(FIG. 9A) and
a clamped position (FIG. 9B). Further, both surfaces may preferably
be oriented in a direction that is transverse to the angle E
referenced in FIG. 8. The angle formed by either or both surfaces
(948 and 950) with respect to the horizontal (i.e., a plane
perpendicular to axis A), and/or the angle E referenced in FIG. 8,
can be determined in a manner deemed suitable on the basis of
different factors including, but not limited to: available, needed
or desired physical dimensions of the setscrew 940 and/or
channel/hole 942; and a desired or needed clamping force as applied
by setscrew 940, with its axial component acting in direction
H1.
[0086] Available physical dimensions of the setscrew 940 and/or
channel/hole 942, for instance, may be constrained by dimension of
a pocket of the shank 912 and/or its associated walls (e.g., such
as the pocket 428 and walls 432 in FIG. 4). Thus, in theory, while
an angle E (as referenced in FIG. 8) may ideally be 90 degrees to
ensure a direct application of an axial clamping force (of setscrew
940 on insert 914), with possible angles of zero degrees formed by
either of both of surfaces 948/950 with respect to the horizontal
(i.e., a plane perpendicular to axis A), in reality various
physical constraints may inform an angle E (as referenced in FIG.
8) of no greater than about 70 to about 80 degrees. However, it
should be noted that one or more variant embodiments may well make
a provision for applying an axial clamping force in a direction
more closely in parallel with respect to axis A; this could be
achieved, e.g., via a concave or angled end surface of setscrew
940, or via a physical extension of (or component physically
attached to) setscrew 940 that extends outwardly from setscrew 940
and itself is oriented in a horizontal direction (i.e.,
perpendicular to axis A).
[0087] FIG. 10 provides a plan view of a shank 1012 in accordance
with at least one variant embodiment, including a wrench tool 1070
for displacing a cutting insert. Here, centering walls 1032 of
pocket 1028 may be disposed, configured and oriented similarly to
the walls 432 shown in FIGS. 4 and 5. Additionally, in another
variant with respect to the main embodiments contemplated with
respect to FIGS. 4 and 5, torque transmission walls 1024 may
themselves be oriented at a similar vertical angle as centering
walls 1032. (Here, it can be understood that the torque
transmission walls 1024 and centering walls 1032 alike are inclined
with respect to the central longitudinal axis and, by extension, to
a plane transverse to the central longitudinal axis.) In a manner
to be appreciated more fully below, a dedicated wrench tool 1070
may be employed to effect a type of clamping and bump-off action as
described heretofore, and analogously so with respect to the
examples of FIGS. 9B and 9C.
[0088] FIG. 11A provides a front elevational view of a shank and
cutting insert in a clamped position, in accordance with at least
one variant embodiment. As shown, the cutting tool 1110 with shank
1112 and cutting insert 1114 may present general similarities to
analogous components shown and described with respect to other
embodiments discussed and illustrated herein. However, analogously
to FIG. 10 discussed above, a radial hole 1172 for including a
wrench tool may also be included, the function of will be
appreciated more fully from the ensuing discussion.
[0089] As such, FIG. 11B provides an axial section taken through
the line 11B-11B in FIG. 11A. As shown, radial hole 1172 may be
regarded as a blind hole, in that it terminates in the central hole
1126 of shank 1112. Similarly to other embodiments discussed and
illustrated herein, centering walls 1132 of shank 1112 may be
dimensioned so as to accommodate cutting insert 1114 via an
interference fit. As such, a wrench tool (such as that indicated at
1070 in FIG. 10) will be selectively removable and insertable with
respect to radial hole 1172; the orientation and function of a
wrench tool therein will be better appreciated from further
discussion herebelow.
[0090] At the same time, there may preferably be provided a
setscrew 1176 which is oriented in a horizontal direction with
respect to cutting insert 1114, or in a direction that is
transverse to central axis A. The setscrew 1176 can reciprocate
within its own channel (that extends in a radial direction with
respect to the axis A), via threaded engagement between the two. To
actuate translational motion of the setscrew 1176 within its own
channel, a wrench tool, such as one as indicated at 1070 in FIG.
10, may be employed to rotate the setscrew 1176 about its own
rotational axis. To this end, a protrusion of the wrench tool may
be inserted in a compatible recess 1178 located at a back end of
the setscrew 1176 (i.e., at an end of the setscrew disposed away
from the axis A).
[0091] It should be appreciated that FIG. 11B illustrates the
cutting insert 1114 in a "clamped" position, analogously to FIG.
9B. As will be better appreciated herebelow, "bump-off" is
facilitated via rotating a wrench tool (such as that indicated at
1070 in FIG. 10) within radial hole 1172, whereby an end protrusion
of the wrench tool contacts a bottom surface of centering pin 1135
and urges the same to move upwardly (i.e., toward the leading edge
end the cutting tool 1110). Also, to permit "bump-off", setscrew
1176 should be translated away from central axis A, to permit
cutting insert 1114 to move axially upwardly in an unhindered
manner.
[0092] FIG. 12A provides a side elevational view of a shank and
cutting insert in accordance with at least one variant embodiment
similar to FIG. 11A, but with a wrench tool 1270 inserted, and in a
position set for "bump-off" or disassembly. Again, the cutting tool
1210 with shank 1212 and cutting insert 1214 may present general
similarities to analogous components shown and described with
respect to other embodiments discussed and illustrated herein,
while the function of wrench tool 1270 may be appreciated more
fully from the ensuing discussion.
[0093] FIG. 12B provides a rear elevational view of the shank and
cutting insert shown in FIG. 12A. Accordingly, shown here in
addition are a setscrew 1276 with a recess 1278, substantially
similar to analogous components in FIG. 11B.
[0094] FIG. 12C provides an axial section taken through the line
12C-12C in FIG. 12B. As shown, the wrench tool 1270 is disposed in
radial hole 1272; again, the latter is embodied as a blind hole
that terminates in the central hole 1226 of shank 1212. Again,
centering walls 1232 of shank 1212 may be dimensioned so as to
accommodate cutting insert 1214 via an interference fit. For its
part, the wrench tool 1270 is selectively removable and insertable
with respect to radial hole 1272, and includes an end protrusion
1274 that may be dimensioned to fit in the space beneath a bottom
portion (i.e., a trailing end portion) of centering pin 1235 of
insert 1214 as shown in FIG. 11A.
[0095] Also shown is the setscrew 1276, oriented in a horizontal
direction with respect to cutting insert 1214, or in a direction
that is transverse to central axis A. The setscrew 1276 can
reciprocate within its own channel (that extends in a radial
direction with respect to the axis A), via threaded engagement
between the two. To actuate translational motion of the setscrew
1276 within its own channel, the wrench tool 1270 may be employed
to rotate the setscrew 1276 about its own rotational axis. To this
end, the protrusion 1274 of wrench tool 1270 may be inserted in the
compatible recess 1278 located at a back end of the setscrew 1276
(i.e., at an end of the setscrew disposed away from the axis
A).
[0096] It should be appreciated that FIG. 12C indeed illustrates
the cutting insert 1214 in a condition ready for "bump-off", or
disassembly, analogously to FIG. 9C. Thus, "bump-off" here will be
facilitated merely via rotating the wrench tool 1270 within its
radial hole 1272, whereby the end protrusion 1274 contacts a bottom
surface of centering pin 1235 and urges the same to move upwardly
(i.e., toward the leading edge end the cutting tool 1210), thereby
releasing the insert 1214 from the pocket centering walls 1232 (and
thus, from the pocket itself). Also, to permit "bump-off", setscrew
1276 (as shown) can be translated away from central axis A, to
permit cutting insert 1214 to move axially upwardly in unhindered
manner.
[0097] FIG. 12D provides an axial section taken through the line
12D-12D in FIG. 12A. As shown, the protrusion 1274 of wrench tool
1270 may be shaped as a stadium (geometric shape) in cross-section.
A curved trough 1280 may thus be provided to accommodate rotational
movement of protrusion 1274, wherein both components are shaped
compatibly to permit such movement. The trough 1280, for its part,
can be understood to be an extension of the radial hole 1272 shown
in FIG. 12A and serve as a support to withstand the force created
by the interaction between protrusion 1274 and the bottom portion
of pin 1235.
[0098] FIG. 13A provides an elevational isometric view of a cutting
insert 1314, in accordance with at least one embodiment. Similar to
the arrangements illustrated in FIGS. 7A-7D, 8, and 9A-9D, cutting
insert 1314 includes a centering pin 1335 in the form of an
elongated body which is coupled to, and extends axially away from,
a main head portion (or head) 1336. As shown in the sectional view
of FIG. 13B, centering pin 1335 may include a threaded portion
1335A disposed at or near a trailing end (not numbered) thereof
which may be cooperatively engaged with a corresponding threaded
aperture 1336A of head portion 1336 such that centering pin 1335
may be coupled or uncoupled from head portion 1336 via rotation of
one or both of components 1335 and/or 1336 about a longitudinal
axis 1370 of centering pin 1335. Such arrangement allows for
cutting insert 1314 to be formed from a different material than
centering pin 1335, which is more cost effective and provides for
greater flexibility of materials which may be utilized for such
components. For example, cutting insert 1314 is preferably formed
from a hard material (e.g., without limitation, carbide) to provide
the best capability for metal cutting. Meanwhile, centering pin
1335 is preferably formed from a material having a high toughness
(e.g., without limitation, steel) in order to avoid distortion in
areas engaged by a setscrew, such as described below. Additionally,
such arrangement provides for centering pin 1335 to be used
multiple times while cutting insert 1314, which is recognized as a
wear part, is replaced after certain use.
[0099] Similar to the arrangements of FIGS. 7A-7D, 8, and 9A-9D, a
recess 1338 is provided in centering pin 1335 generally near a
leading end (not numbered) of centering pin 1335 to accommodate a
setscrew (such as setscrew 1340 shown in FIG. 14 and described
below), in a manner to be more fully appreciated herebelow. In the
example embodiment illustrated in FIG. 13A, recess 1338 is bounded
by a continuous periphery P which is disposed at the outer surface
of centering pin 1335 such that recess 1335 may be considered to be
at least partially enclosed by centering pin 1335. Also shown in
FIG. 13A are cutting edges 1320, drive surfaces 1322 and a cutting
tip 1317 of head portion 1336 which may be regarded as analogous to
similar components described and illustrated elsewhere herein.
[0100] FIG. 13B, which provides a sectional view taken along
13B-13B in FIG. 13A (and along longitudinal axis 1370), along with
FIG. 13C which shows a detailed view of the portion of FIG. 13B
generally indicated at C, illustrate some elements and viable
proportional dimensions of recess 1338 which interact with
corresponding portions of a setscrew 1340 such as shown in FIG. 14
and described below. As shown in FIG. 13C, in accordance with at
least one embodiment, recess 1338 includes a first angled surface
1350, disposed generally facing away from the leading end of
centering pin 1335 (i.e., surface 1350 generally faces toward head
portion 1336). First angled surface 1350 is oriented at an acute
first angle .alpha. with respect to longitudinal axis 1370 of
centering pin 1335. First angle .alpha. may be in the range of
30.degree. to 85.degree., and in the example illustrated embodiment
is about 45.degree..
[0101] Continuing to refer to FIG. 13C, recess 1338 further
includes a second angled surface 1352 which is positioned opposing
first angled surface 1350 (i.e., facing generally toward the
leading end of centering pin 1335) at an acute second angle .beta.
with respect to longitudinal axis 1370 of centering pin 1335.
Similar to first angle .alpha., second angle .beta. may be in the
range of 30.degree. to 85.degree., and in the example illustrated
embodiment is about 45.degree.. It is to be appreciated that as
used with respect to the first angled surface 1350 and the second
angled surface 1352, the term "opposing" shall mean that the two
surfaces face each other and are oriented so as to form an angle
therebetween which is less than 60.degree., preferably around
30.degree. or less, and most preferably 0.degree. (i.e., preferably
the two surfaces are parallel).
[0102] As shown in FIG. 13D, which is a sectional view of centering
pin 1335 taken through the line 13D-13D of FIG. 13B facing toward
second angled surface 1352, a cutout region 1353 is provided in
second angled surface 1352. In the illustrated example, cutout
region 1353 is generally disposed about a recess axis 1390 which
preferably is disposed at a right angle with respect to first
angled surface 1350 and second angled surface 1352. As will
appreciated from the further description below, a 90.degree. angle
is preferred since this gives the best surface contact between
rotating surfaces on setscrew 1340 and corresponding axial sliding
surfaces within cutout region 1353 of centering pin 1335. Other
angles from 70 to 89.degree. would still enable similar function
but reduce transmittable forces due to change from a full face
contact to line or point contacts.
[0103] Referring now to FIG. 14, setscrew 1340 for use with cutting
insert 1314 includes a threaded main shaft portion 1344, disposed
about a central longitudinal axis 1341, and a head portion 1346,
with a narrowed neck region 1347 disposed therebetween. Head
portion 1346, as shown, may be generally cylindrical. Head portion
1346 is defined in-part by a clamping surface 1348 disposed at a
distal end of setscrew 1340 (i.e., an end disposed toward the
insert 1314 with respect to an axial direction of the setscrew
1340). Head portion 1346 is further defined on an opposing side
from clamping surface 1348 by a bump surface 1364. In the example
illustrated embodiment clamping surface 1348 and bump surface 1364
are formed as flat surfaces disposed at 90.degree. to longitudinal
axis 1341 as such arrangement provides the best surface contact
between such surfaces and corresponding surfaces of cutout region
1353 of centering pin 1335 as discussed further below.
[0104] Similar to setscrews 840 and 940 previously discussed in
conjunction with FIGS. 8 and 9A-9C, setscrew 1340 may be threadedly
engaged in a compatible channel of a shank in order to translate in
parallel to its own central longitudinal axis 1341 in order to
engage or disengage with recess 1334 of insert 1314 in a manner to
be more fully appreciated below. To this end, it may be actuated at
a rear portion thereof (i.e., at that end portion disposed away
from head portion 1346), via a wrench tool or other suitable
arrangement that can displace setscrew 1340 in a rotational
direction (about its own central longitudinal axis 1341) to thereby
translate the setscrew 1340 with respect to a shank via the
aforementioned threaded engagement.
[0105] FIG. 15A shows an example cutting tool 1310 in which
setscrew 1340 is disposed in a dedicated channel (or hole) 1342
formed in a generally cylindrical shank 1312 in a manner such that
setscrew 1340 can reciprocally translate within the channel/hole
1342. As noted above, such movement may be promoted via mutual
threaded engagement between setscrew 1340 and channel/hole
1342.
[0106] For clamping, setscrew 1340 can be positioned such that
longitudinal axis 1341 thereof is positioned generally parallel to
recess axis 1390 of recess 1338 such that clamping surface 1348 of
setscrew 1340 will fully engage first angled surface 1350 of
centering pin 1335, thus creating an axial clamping force that
urges centering pin 1335, and thus cutting insert 1314 in a
direction H1 as shown in FIG. 15B. A parallel arrangement of axis
1341 and 1390 is preferred since this gives the best surface
contact between the rotating surfaces (i.e., clamping surface 1348
or bump surface 1346) on setscrew 1340 and the corresponding axial
sliding surfaces (i.e., first angled surface 1350 or second angled
surface 1352) of recess 1338 of centering pin 1335. It is to be
appreciated, however, that other angles from 1.degree. to
10.degree. would still enable similar function but would reduce
transmittable forces due to change from a full face contact to line
or point contacts.
[0107] As shown, the shank 1312 includes a central hole 1326 for
accommodating the centering pin 1335 of cutting insert 1314.
Preferably, the centering pin 1335 will have a precise slide fit
with respect to the central hole 1326. As such, the side component
of the clamping force created by the setscrew 1340 will be
supported by the wall of hole 1326, thus preventing excessive
displacement of the centering pin 1335. It can be appreciated that
any such excessive displacement could otherwise cause the insert
1314 to lose its concentricity with the axis of rotation A, and/or
cause breakage of the pin 1335. The combination of a precise fit
between centering pin 1335 and hole 1326, in conjunction with an
interference fit between insert 1314 and a pocket of shank 1312
(such as pocket 428 in FIG. 4) will ensure that the insert 1314 is
clamped in a correct position and remains stable in its position
during operation. As such, it can be appreciated that in at
accordance with at least one embodiment the hole 1326 and pin 1335
may assume a circular cross-section when viewed two-dimensionally
(in a plane transverse to axis A), and a generally cylindrical
configuration when viewed three-dimensionally. However, in
accordance with at least one variant embodiment, the hole 1326 and
pin 1335 may assume any of a wide variety of other possible
two-dimensional cross-sectional shapes, e.g., an oblong (stadium)
or elliptical shape.
[0108] To help ensure that the centering pin 1335 (and cutting
insert 1314) initially sits at a predetermined position for proper
engagement with the front portion 1346 of setscrew 1340, centering
pin 1335 may include a circumferential groove 1380 extending around
centering pin 1335 near head portion 1336 having a deformable
element, such as an o-ring 1356, fitted partially therein.
Preferably, the deformable element 1356 provides a frictional fit
against the wall of hole 1326 in a manner such that centering pin
1335 may generally be initially inserted into hole 1326 of shank
1312, such as shown in the positioning of FIG. 15A, and such that
centering pin 1335 may be removed from hole 1326 with a minimal
force without the need for additional tooling. Additionally, the
deformable element 1356 provides a seal, keeping possible
contaminants from hole 1326 and the interacting surfaces of pocket
1338 and setscrew 1340.
[0109] As shown, in FIG. 15B, as setscrew 1340 is translated into
hole/channel 1342, the entire clamping surface 1348 of setscrew
1340 contacts the first angled surface 1350 of shaft 1335. The
manner of engagement between setscrew 1340 and shaft 1335 then
changes in a manner to be appreciated more fully herebelow.
[0110] FIG. 15D schematically illustrates cutting insert 1314 and
setscrew 1340 of FIGS. 15A and 15B, but in a "clamped" position. To
achieve such a "clamped" position, the setscrew 1340 was translated
within channel 1342 (e.g., via rotation and the aforementioned
threaded engagement), in a direction Gl, to cause the centering pin
1335 (and thus the cutting insert 1314) to move axially downwardly
(i.e., in direction H1) as clamping surface 1348 of setscrew 1340
is rotated about axis 1341 and translates (via corresponding
downward movement of centering pin 1335) along first angled surface
1350 of recess 1338 toward axis 1390. Such interaction between
clamping surface 1348 and first angled surface 1350 causes the
entire cutting insert 1314 to move axially downwardly in a pocket
of the shank 1312 (e.g., such as pocket 428 in FIGS. 4 and 5),
whereupon centering walls of the pocket (e.g., such as walls 432 in
FIGS. 4 and 5) will deform elastically in a radially outward
direction (with respect to axis A). This will then promote an
interference fit of the insert 1314 within shank 1312 (as also
discussed hereabove), such that the insert 1314 is then securely
clamped within shank 1312. As shown in FIG. 15F (which is a detail
view of a portion of FIG. 15D), when disposed in the "clamped
position", bump surface 1364 of setscrew 1340 is spaced a clearance
distance d from second angled surface 1352.
[0111] In accordance with at least one embodiment, FIG. 15E
schematically illustrates the cutting insert 1314 and setscrew 1340
of FIGS. 15A-D, with the insert still in a "clamped" position and
but with the setscrew 1340 already positioned for bump-off (i.e.,
setscrew 1340 has been translated within channel 1342 in the
direction opposite of that previously described) such that the
clearance distance d which previously existed between second angled
surface 1352 and bump surface 1364 now instead exists between
clamping surface 1348 and first angled surface 1350. As such, the
"bump-off" action takes place when the setscrew 1340 undergoes
reverse translational movement, as indicated by arrow G2, and bump
surface 1364 of head portion 1346 is rotated about axis 1341 and
translates (via corresponding upward movement of centering pin
1335) along second angled surface 1352 of recess 1338 away from
axis 1390. Such interaction between surfaces 1352 and 1364 causes
the centering pin 1335 (and cutting insert 1314) to displace
axially in a "return" direction as indicated by arrow H2. The
insert 1314 will be pushed out of the pocket and must overcome the
frictional forces exerted by the pocket walls (due to interference
fit).
[0112] FIG. 15H shows a sectional view, similar to FIG. 13D, which
shows, the interaction area X (shown in cross-hatching) between
bump surface 1364 of head portion 1346 and second angled surface
1352. It is thus to be readily appreciated that such arrangement of
neck region 1347 and bump surface 1364 of setscrew 1340 along with
second angled surface 1352 and cutout region 1353 of recess 1338 of
centering pin 1335 provides for an interaction area X which
generally encompasses an angle y about recess axis 1390 of recess
1338 (and longitudinal axis 1341 of setscrew 1340) of at least
160.degree., and preferably more than such value. Angle .gamma. may
be as much as 330.degree.. Such interaction area provides for a
large contact surface which is more robust than previous solutions
and provides for improved reliability and increased component
life.
[0113] This disclosure has been presented for purposes of
illustration and description but is not intended to be exhaustive
or limiting. Many modifications and variations will be apparent to
those of ordinary skill in the art. The embodiments were chosen and
described in order to explain principles and practical application,
and to enable others of ordinary skill in the art to understand the
disclosure.
[0114] Although illustrative embodiments of the invention have been
described herein with reference to the accompanying drawings, it is
to be understood that the embodiments of the invention are not
limited to those precise embodiments, and that various other
changes and modifications may be affected therein by one skilled in
the art without departing from the scope or spirit of the
disclosure.
* * * * *